Azo dyestuffs of the stilbene series



Patented Feb. 18, 1941 l 2,232,078 AZO DYESTUFFS OF THEST'ILBENE spams- Hans, schii'idhelm, Bergen-Enkh'eim; near Frankfort-on-the-Main; Germany; assignor .to General Aniline & Film Corporation, .ascorporation .1

of Delaware No Drawing. Application August 12,'1939,"Seria'l No. 289,783. In Germany August 18,1938

4 Claims.

The present invention relates to new azodyestuffsflof the stilbene series more particularly to those of the general formula:

wherein R and R1 stand for aromatic radicles of the naphthalene series and A st ands for amember selected fromthe group consisting of aromatictradicles of the benzene and naphthaleneseries, the two nitrogen atoms being attached tolA in para-position to each other.

I, The .new ldyestuffs may be prepared in the ll'i'following J manner: 4-nitro-4'-amino stilbene- 2.2-disulfonic acid is diazotized and combined with an amine of the naphthalene seriesf coupllngin o position 'to'the amino group,-and in the o-amino-azodyestuff formed the am group and the amino group-are converted into the triazole ring according to known methods. Then the nitro group in the 4-position of the stilbene radicle is'reduced to the amino group, the amino compoundwformed is diazotized and the diazo compound obtained is combined with an amine coupling in para-position to the amino group. The.=amino-monoazodyestufi thus obtained is further acid; is idiazotized and. the [diazo compound formed is combined with'an amine coupling in para-position to the amino group, then the nitro group is" reduced and the diamino-monoazodyestuff obtained is tetrazotized and the tetrazo compound formed is combined with 2 molecular proportions of an amine of the naphthalene series coupling in ortho-position to the amino group. Finally the formation of the two triazole rings is performed. One may also start from 4.4'-diaminostilbene-2.2-disulfonic acid, which compound is tetrazotized and combined only on one side of the molecule with 1 molecular proportion of an amine coupling in para-position to the amino group. The intermediate product thus obtained is then further diazotized and the tetrazo compound obtained is combined with 55 two molecular proportions of an amine of the diazotized and: the: diazo compound formed is combined with an amine of the naphnaphthalene'series coupling 'in o-position to the amino group, whereupon the formation of the two triazole' rings is performed. v

The new dyestuffs are distinguished by a good afiinity for vegetable fibers and by clear shades and excellent fastness to light of the dyeings obtained. I

In order to further illustrate my invention the following examples are given, the parts being by weight'and all temperatures in degrees centigrade.

Erample 1 602 parts of the amino-triazole compound which is obtained by combining diazotized 4- nitro-4-'aminostilbene-2.2'-disulfonic acid with 1-aminonaphthalene-4-sulfonic acid, converting. the amine group and the azo group into the triazole ring and reducing the nitro group .in the 4-position of the stilbene radicle, are diazotized in the usual manner. The diazo compound formed is combined with 250 parts of the sodium salt of 1-aminonaphthalene-7-sulfonic acid in an aqueous solution containing an excess of sodium carbonate. When the combination is complete, the aminoazodyestufi .formed is precipitated by the additionof sodium chloride,,filtered off and again dissolved in water. After the addition of 1 69 parts of sodium nitrite the solution is poured into hydrochloric acid and the diazo compound formed is combined with 143 parts of 2-aminonaphthalene. When the combination is. complete, the. disazodyestufif. obtained is separated and purified by washing with a sodium chloride solution of 24? B. Then it is dissolved in water and converted'into the corresponding di-trlazole compound by theaddition of 520 parts of copper sulfate in the presence of ammonia.

The new dyestufi thus obtained corresponds to theformula:

| SOaNa S OsNa 8 S OaNa' SOsNa Similar dyestuffs are obtained by employing as end component instead of the 2-aminonaphthalene the carboxylic or sulfonic acid derivatives thereof or by employing other triazole compounds 5 of the stilbene series as initial components.

Example 2 602 parts of the amino-triazole compound which is obtained by combining diazotized 4- nitro-4'-aminostilbene-2.2'-disulfonic acid with 2-aminonaphthalene-G-sulfonic acid, converting the amino group and the azo group into the triazole ring and reducing the nitro group in the 4-position of the stilbene radicle, ar diazotized in the usual manner. The diazo solution obtained is combined in the presence of a mineral acid with 153 parts of l-aminonaphthalene. The aminoazodyestufi formed is separated, purified and diazotized in the usual manner, and the diazo compound obtainedis combined with 187 parts of 2-aminonaphthalener3-carboxylic acid in an aqueous solution containing an excess of sodium carbonate. When the combination is complete, the disazodyestuff formed is treated in the presence of sodium hydroxide with an excess of sodium hypochlorite solutionwhereby oxidation takes place and the shade is changed from grey to orange.

The new dyestuff thus obtained corresponds to the formula:

some I s It.is, when dry,'an orange powder, soluble in 40 'water with an orange and in concentrated sulfuri'c acid witha blue color; dyeing cotton orange shades of 'very good fastness to light.

Example 3 3 I 602- parts of the triazole compound employed in Example 1 as starting material arediazotized and combined in a mineral acid containing solution with 107'parts of S-amino -l-methy'rlbengene. The aminoazo dyestufi obtained is diazotizedinthe usual manner and the diaz'o compound formed is combined with 250 parts of the sodium salt of 1-amino naphthalene-l-sulfonic acid. The diazod-yestuff formed is isolated, freed ;from impurities, redissolved and oxidized by means of sodium hypochlorite in the presence of sodium hydroxide. Then-the di-triazole formed is separated, washed and dried; it is an orange powdersoluble in water with a clear yellowcolor and in concentrated sulfuric acid with a bluish red color.

' which dyestuif is an orange powder, dyei'ng'yeg'e ness-to light.

The new dyestuff corresponds to the formula:

SOiNii v SOzNa It dyes cotton clear yellow shades of excellent fastness to light. 10

Somewhat more greenish shades are obtained when employing for the manufacture of the above described ,dyestufi aniline instead of the 1- methyl-3-aminobenzene.

I claim: 15

1. The azodyestuffs of the stilbene series of the general formula:

wherein R and R1 stand for aromatic radicles 015 I, the naphthalene series and A stands foramember selected from the group consisting of are matic radicles of the benzeneand naphthalene 25 series, the two nitrogen atoms being attached 2 to A in paraposition to each other, which dyestuiTs dye vegetable fibers clear shades of excellent fastness to light. i 4

aNa which dyestuff is an orange powder, dyeing vegetable fibers orange shades of very good-fastness tolight. z 4. The azodyestufi of the formula? .1

NNQQH=CHON=N N-nl. L l/ some a tablefibers clear yellow shades of excelleht'fast He -tea m tes; 1; 

